Use python class special methods to add idiomatic behavior to your class.
“It is the time you have wasted for your rose that makes your rose so important.” ― Antoine de Saint-Exupéry, The Little Prince
The python class system supports a number of special methods which allows class implementations to mimic built-in python objects objects. These special methods are invoked by the python run-time system in a way similar to the built-in classes. For example, the method __len__() can be defined by a user class which will be invoked when the client code attempts to find the length of the object using len(obj).
Continue reading “Python Class Methods – Implementing Ordered Dictionary”
Learn how to declare and use nested classes in python
“There is nothing either good or bad, but thinking makes it so.” ― William Shakespeare, Hamlet
A nested or inner class is contained within another class. This could be for reasons of encapsulation, where the inner class is not useful by itself. Continue reading “Nested or Inner Classes in Python”
Here is a beginner’s introduction to classes in python
“Sometimes it’s worth lingering on the journey for a while before getting to the destination.” ― Richelle Mead, The Indigo Spell
The concept of a class is the core of Object Oriented Programming. It defines a blue-print for constructing objects. It is a plan of how an object is laid out, including its data members, instance methods, class methods and inheritance hierarchy. Python supports object oriented programming and classes, although with certain differences from other languages like C++ and Java. In this article, we shall delve into python classes and learn how they work.
Continue reading “An Introduction to Python Classes”
Convert one value to another in a Streams Operation
“Always and never are two words you should always remember never to use. ” ― Wendell Johnson
Do you know about Java 8 Streams?
Java 8 streams is a very powerful facility for working with collections. What formerly required multiple lines of code and loops can now be accomplished with a single line of code. A part of Java 8 streams is the map() facility which can map one value to another in a stream. In this article, let us examine some common use cases where map() is useful.
Continue reading “Java 8 Streams Map Examples”
Extend your application’s usability with a scripting interface
“Success is not how high you have climbed, but how you make a positive difference to the world.” ― Roy T. Bennett, The Light in the Heart
A non-trivial program of any type has a reasonably complex interface and probably supports multiple options with several ways of controlling input and output. Invoking such a program can be done via the command line, but here we run into limitations of what you can do with the command line. You can probably add options for all supported settings and multiple modes for the program to run.
Learn how to automate tasks on the web using Selenium
“Indifference and neglect often do much more damage than outright dislike.” ― J.K. Rowling, Harry Potter and the Order of the Phoenix
Selenium is a handy tool for controlling a web browser (such as Google Chrome) through a program. It allows you to automate tasks on a website by using the browser much the same way a human user would. Such automation can be useful for a variety of tasks including: regression testing of web applications, data extraction and more. In this article, we will learn how to use Selenium to drive the Chrome Browser.
Continue reading “How to use Selenium for Driving the Chrome Browser”
Use XQuery for more powerful XML search than is possible with XPath
“I guess there are never enough books.” ― John Steinbeck, A John Steinbeck Encyclopedia
XPath offers an easy way to search an XML document using java. It is much more convenient than having to crawl through the document tree using the DOM API. XQuery builds on XPath and provides an SQL-like language for querying XML documents. It is also capable of updating and modifying the XML document, something which XPath cannot do. In this article, we present a beginner’s introduction to XQuery and how to use it from java.
Continue reading “How to Search XML Using XQuery from Java”
Use XQuery to Query, Update and Modify XML Documents
“Trees that are slow to grow bear the best fruit.” ― Molière
As a Java Programmer, if you work in any way with XML, you should learn about XQuery and how to use it.
XQuery is a query language for XML. It is similar to XPath in that it uses the same or similar constructs to identify specific parts of an XML document.
Continue reading “How to Install and Use Oracle XQuery Processor for Java”
Use XSL Tranformation to Pretty Print and XPath to remove indentation
“Time is a drug. Too much of it kills you.” ― Terry Pratchett, Small Gods
XML is easiest to understand when it is properly indented to indicate the element hierarchy. However the extra space added to XML when it is transported increases file sizes. So it makes sense to remove all extraneous information from the document, including ignorable white space. This article will show you how to indent and pretty print an XML document.
Continue reading “How to Pretty Print XML from Java?”
JAXB converts XML to Java and Jackson handles the Java to JSON Conversion
“You only live once, but if you do it right, once is enough.” ― Mae West
In a previous article we covered the basics of using JAXB with its annotations to convert java objects to XML and back. In this article, we take a look at converting from XML to JSON and back, using jackson for the JSON conversion.
Continue reading “Converting Between XML and JSON Using JAXB and Jackson”